Prepare the gravy according to the recipe. Cover, and set aside.
Cut the tempeh into ¼-thick slices crosswise, then cut these in half length to get shorter strips.
Heat the oil and soy sauce slowly in a skillet or stir-fry pan, then add the tempeh strips and green beans, and stir gently to coat. Sauté over medium heat for 2 to 3 minutes, stirring frequently.
Stir in the bell pepper and turn the heat to medium-high. Continue to sauté, stirring frequently, for 5 minutes longer, or until the bell pepper and green beans are tender-crisp.
Stir in scallions. You can add the gravy now and serve straight from the pan, or transfer the tempeh and green bean mixture to a serving platter and pass the gravy around in a separate container. Either way, serve at once.